The invention relates to a switchable energy storage device and to a method for operating a switchable energy storage device.
Power electronics systems which are intended both for use in stationary applications (for example in wind turbines) and in vehicles (for example hybrid and electric vehicles) and which combine new battery technologies with known electrical drive technologies are known from the prior art. Such systems comprise, for example, a pulse-controlled inverter, with which an electric machine (for example a rotating-field machine) is fed in terms of energy. A typical such system is a DC link, via which a battery is connected to a DC voltage side of the inverter. In order that the battery can provide the required power and energy data, individual battery cells are connected in series and sometimes additionally in parallel.
DE 10 2010 041 059 A1 discloses a method for setting a setpoint output voltage of an energy supply branch of a controllable energy store which is used for controlling and supplying electrical energy to an n-phase electric machine, where n≧1. In this case, the controllable energy store has n parallel energy supply branches, which each have at least two series-connected energy storage modules, which each comprise at least one electrical energy storage cell comprising an associated controllable coupling unit. The energy storage modules are connected firstly to a reference rail and secondly to in each case one phase of the electric machine.